Governmental regulations enacted in recent years concerning the disposal of hazardous materials prohibit removing surface soils by scrubbing the surface and flushing the removed soil down a drain with water. The soil that is removed must be collected and transported to an approved disposal facility.
Appliances have been devised which reportedly were capable of cleaning hard surfaces. U.S. Pat. No. 3,189,930 granted Jun. 22, 1925 to H. G. Tuthill, Jr. for "Surface Cleaning Apparatus" discloses such an appliance. However, because Tuthill relied primarily oft rotating brush action to loosen soil, his appliance was more suited for carpet cleaning than removing hard-to-remove stains from concrete.
Carl R. Young in his U.S. Pat. No. 5,135,015 granted Aug. 4, 1992 for "Pressurized Fluid Cleaning Device" recognized the capability of high pressure liquid spray from a rotating nozzle assembly to loosen soil and debris. Young's appliance does not comply with current regulations because in cannot retrieve the loosened soil.
U.S. Pat. Nos. 4,191,589 granted Mar. 4, 1980 to K. F. Halls et al for "Method and Apparatus for Cleaning Carpets and Surfaces Using Cleaning Fluid" and 4,377,018 granted Mar. 22, 1983 to G. E. Cain for "Cleaning Devices for Surfaces" combine serf propelling rotatable spray nozzle assemblies with adjoining vacuum nozzles for removing the soil. The disposition of the vacuum nozzle in these appliances limits their effectiveness and versatility. For example, in use the Halls et al appliance must be drawn rearwardly in a straight line. And the vacuum hood of the Cain appliance likely gave uneven performance across its width.
The inventors identified in two prior patents sought to improve the vacuum withdrawal of soil by providing bell-shaped vacuum hoods with flexible sealing skirts at their lower peripheries. Their patents are U.S. Pat. No. 4,037,290 granted Jul. 26, 1977 to J. J. Rose et al for "Vacuum Cleaning Device" and U.S. Pat. No. 4,107,816 granted Aug. 22, 1978 to P. W. Matthews for "Cleaning Heads". Both inventors preferred to provide a motor for rotating spray nozzles in the hoods. Rose et al employed an air jet nozzle while Matthews chose to spray cleaning water. Neither of these two appliances offers a particularly effective vacuum soil removing system.
There continues to be a need for a hard surface cleaning appliance which effectively loosens soil from the surface and removes and captures the soil and spent cleaning fluid.